Propose to combine standard commercial CZT crystals and ASICS with Aguila Technologies' proprietary high-density CZT detector bonding methods and very dense electronic packaging capability to develop high resolution (less than 1 mm pixel pitch) imaging CZT gamma detectors. The aim is that the proposed detector modules could be manufactured in large quantities relatively inexpensively. The proposed detector module will comprise a single 19.6 x 19.6 x 5-mm CZT crystal in a high-density sensor package that will include four ASIC readout chips. The crystals will be partitioned into 512 anodes. Pixel pitch will be about 850-mu m, with 50-mu m streets and a 100-mu m border. The readout ASIC chips are mounted on an interposer card that is, in-turn, flip-chip bonded to the CZT array on one side and an array connector on the other. The proposed detector with its four readout ASICs will be assembled into small, self-contained modules that can be plugged into an array of sockets on a motherboard to create a large tiled array of sensors with no dead space between them. A central program objective is to fabricate and deliver to investigators in the field of small animal gamma ray imaging fully functional detector modules and test boards to integrate the detectors into functional imaging systems.